<!DOCTYPE html>
<!--60.尚硅谷_css3_flex(新版本项目新增)-->
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style>
			/*
			 flex-grow
			 box-flex 默认值都为0
			 
			 flex-grow:
			 		可用空间 = (容器大小 - 所有相邻项目flex-basis的总和)
			 					400 - 5 * 50 = 150
			 					
			 				#wrap > .item{flex-basis: 0;}时:
			 					400 - 5 * 0 = 400	
			 					
			 		可扩展空间 = (可用空间/所有相邻项目flex-grow的总和)
			 					150 / 8 = 18.75
			 					
			 				#wrap > .item{flex-basis: 0;}时:
			 					400 / 8 = 50
			 					
			 		每项伸缩大小 = (伸缩基准值  + (可扩展空间  x flex-grow值))
			 					50 + 18.75 * 4 = 125
			 					50 + 18.75 * 1 = 68.75
			 					
			 				#wrap > .item{flex-basis: 0;}时:
			 					0 + 50 * 4 = 200
			 					0 + 50 * 1 = 50
			 * */
			*{
				margin: 0;
				padding: 0;
			}
			#wrap{
				width: 400px;
				height: 300px;
				border: 1px solid;
				margin: 100px auto;
				display: flex;
				flex-direction: row;
				justify-content: flex-start;
				align-items: flex-start;
			}
			#wrap > .item{
				width: 50px;
				height: 50px;
				background: pink;
				text-align: center;
				line-height: 50px;	
				flex-grow: 1;	
				flex-basis: 0;	
			}
			#wrap > .item:nth-child(1){
				flex-grow: 4;
			}
		</style>
	</head>
	<body>
		<div id="wrap">
			<div class="item">1</div>
			<div class="item">2</div>
			<div class="item">3</div>
			<div class="item">4</div>
			<div class="item">5</div>
		</div>
	</body>
</html>
